Avtodizel ???-238??, Operating Instructions Manual, Page: 56 / 254

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which enters into the slot in the pump housing boring. In the tappet is
screwed-in the adjusting bolt 3, which locked with nut 2 and serves for
adjusting of fuel supply beginning.
For change of amount of supplied fuel the plunger in the barrel
12 is turned with rotary bushing 4 having gear ring 5 that is gearing
with rack 14.
The adjusting of fuel supply on a nominal mode by each section
of the pump is made by turn of the bushing 4 relative gear rings 5 at
the loosened of a gear ring fastening screw.
In the upper part of the pump housing there are the inlet and
outlet channels, on which the fuel supplied to plunger – barrel pair.
From the governor side the channels are closed with plugs with rubber
rings. From the advance coupling side to the inlet channel joins inlet
pipeline, and on outlet one through the by-pass valve superfluous fuel
is removed.
The longitudinal channels from the side of fuel inlet are
connected with the cross channel. The hole for air release is closed
with a plug 7 (fig. 25).
The work of section proceeds as follows. At movement of the
plunger 13 downwards under action of spring 16, fuel, under low pres-
sure that the fuel feed pump creates in supplying channel, fills the
above-plunger space
At up-wards movement of the plunger fuel is by-
passed in the fuel-supplying channel so long as the plunger end face
edge closes the barrel inlet hole. At the further movement of the
plunger up-wards pressure in above-plunger space grows. When pres-
sure will reach the value, that will exceed the force created by the in-
jector spring, the injector needle will rise and
the fuel injection process
in the engine cylinder will begin. In process of plunger movement up-
wards there comes the moment, when plunger edge opens the cutting-
off hole on the barrel, that causes fall of pressure in pipeline.
Thus
unloading belt of the delivery valve 10, being immersed in the case 11
under action of a spring 9, increases volume in pipeline between injec-
tor and valve.
With that is reached more precise cutting-off of fuel
delivery.
The amount of supplied fuel is dosed by change of the moment
of the supply end at its constant beginning. At moving of the rack the
plunger turns, and adjusting edge opens the barrel hole earlier or later,
owing to the duration of delivery, and, hence, amount of supplying fuel
changes.
On a plunger surface there is a ring groove, and in the plunger
barrel
–
a radial hole for removal of fuel filtered through the plunger-